Homology modelling of 3-oxoacyl-acyl carrier protein synthase II from Mycobacterium tuberculosis H37Rv and molecular docking for exploration of drugs.

Fatty acid synthesis is essential for cell growth and viability. The 3-oxoacyl-acyl carrier protein synthase II (KAS II) from Mycobacterium tuberculosis catalyses initiation of the fatty acid synthesis pathway by condensation of acyl CoA and mycolic acid during the elongation phase. KAS II is a key regulator of bacterial fatty acid synthesis, and a promising target in the search for potent antibacterial drugs. Homology modelling was used to generate the 3-D protein structure using the known crystal structure, and the stereochemical quality of KAS II was validated. Effective drugs were selected that target the active amino acid residues of KAS II. The drugs thiolactomycin, thiophenone and the multidrug cerulenin isoniazed were found to be more potent for inhibition of M. tuberculosis due to the robust binding affinity of their protein-drug interactions. KAS II enzymes of M. tuberculosis and other species of Mycobacterium are conserved, as revealed by their close phylogenetic relationships. This study may provide new insights towards understanding the 3-D structural conformation and active amino acids of KAS II, thus providing rationale for the design of novel antibacterial drugs.